The present invention relates to removal of intervertebral disc material. More particularly, it relates to a method and powered device for removing some or all of the material (tissue, cartilaginous bone, etc.) associated with an intervertebral disc, for example in performing a nucleotomy.
The vertebral spine includes, amongst other structures, a series of bony vertebrae, adjacent ones of which are supported and separated by an intervertebral disc. In a healthy spine, the discs maintain separation between the vertebrae, promoting fluid circulation throughout the spine, and providing a cushioning effect between the vertebral structures. An intervertebral disc generally includes an annulus fibrosis (or “annulus”), a nucleus pulposus (or “nucleus”), and opposing end plates. The end plates are akin to cartilaginous bone and serve to attach adjacent vertebrae to the disc. The nucleus is disposed between the end plates, circumferentially constrained by the annulus.
Intervertebral discs are elastic in nature, and can be damaged or displaced. For example, intervertebral discs can be overtly stressed by excessive movement, excess body weight, injury, disease, and/or gradual deterioration with age. Intervertebral disc injuries or other abnormalities can result in serious back pain and physical disability, and are often chronic and difficult to treat. For example, the annulus may bulge or tear, with the distended nucleus tissue compressing against a spinal nerve (e.g., disc herniation). Similarly, the disc may degenerate over time, leading to a collapse of the disc space.
Surgical procedures have been developed to repair damage or displaced intervertebral discs. These procedures include nucleotomies or discectomies in which a portion (e.g., the nucleus), or an entirety of the intervertebral disc is excised. Fusion is another accepted technique and entails the bony portions of the spine being fused together to limit the relative motion between adjacent vertebrae. Insertion/implantation of the fusion-inducing device(s) again requires removal of certain discal tissue. Similarly, disc decompression/fusion procedures require forming a hole in the annulus possibly followed by removal of nucleus tissue prior to backfilling with fusion material. More recently, nucleus replacement implants have been developed; these products also require removal of discal tissue (i.e., the nucleus and/or portions of, or all of, the annulus) prior to implantation.
Regardless of the exact procedure, various manual instruments for the removal of intervertebral disc material(s) are conventionally employed. These manual instruments include osteotomes, surgical chisels, guillotine cutting devices, etc. The highly confined nature of the surgical site associated with the intervertebral disc, the delicate surrounding structures (e.g., nerves), and the wide-range of material to be cut (i.e., the nucleus tissue is fairly soft, whereas the annulus tissue is quite tough), have likely given rise to the reliance upon simple, manual devices. While viable, use of manual instrumentation can render the procedure overly time consuming. Often times, several different manual instruments must be passed in and out of the surgical site multiple times in order to remove the desired discal material. This increases the chance of damage to sensitive structures adjacent to the spine (vascular and nervous). The manual instruments also require separate irrigation and suction device(s) to clean the surgical site during and after the procedure. Further, for certain procedures such as nucleotomies, manual surgical instruments require a surgeon to rely upon tactile feel to ensure that the annulus is not violated.
Injured and degenerated intervertebral discs pose serious health problems to a large number of patients. Many current and future treatments require the removal of nucleus and/or other discal tissue. Manual intervertebral disc material-removing tools are time-consuming to use, and require multiple other instruments. Available powered instruments for cutting intervertebral disc material do not afford the ability to deftly shave only targeted bodily structures, an attribute essentially required by the anatomy forming and surrounding the intervertebral disc. Further, available powered instruments may not be able to adequately cut the disparate bodily materials (in terms of hardness and toughness) typically presented by an intervertebral disc. Any advancement in the tools and related methods for performing this delicate material removal within or at the disc space will be well-received.